hi
i bought a infrared thermometer and would like to know what the temp should be for a os 46 ax and a fx 61 ,thanks

The info you get by using the thermometer will be useless, the engine temperature depends on a whole lot of factors, for example, ambient temperature, nitro percentage, amount of oil in the fuel, prop diameter, whether the engine is coweled or not, even which glow plug is installed. No one is going be able to give you a usable answer. Sorry

Pretty much what Hobbsy said although I use a thermocouple to check head temps on the test stand but only for interest's sake. When an engine is tuned correctly (meaning slightly rich and definitely not lean) then the temp will be what it will be. What the temp gauge can be useful for though is comparing the temps on a particular engine when changing something like oil content or fuel brand. With an infrared thermometer you have to be careful to always aim at the same place and the base of the glow plug is the best spot because virtually all engines have the same thickness of metal at that point.

Our engines do not overheat to the point of failure, failure is from lack of oil from a lean mixture. When converted to gas the normal operating temp often exceed the over lean temps on our alcohol based fuel. So the themometer is pretty much useless. Use a tachometer instead. Lean to maximum RPM then enrich till you get a 300 to 400 RPM drop.

In parallel with the others, above, our experience in the service shop has shown that reliance on temperature to set your engine is a sure way to shorten its operating life. However, once you have the engine tuned correctly, temp checking can alert you to something going wrong, though paying attention to RPM and exhaust sound will usually do the job sooner and more accurately.

Does it sizzle spit? If so you'll cook it. Spit my vaporize rather quickly but it shouldn't sizzle and dance around. Thats just a quick way to tell without burning your finger.